In a hearing aid, acoustical signals arriving at a microphone of the hearing aid are amplified and output with a speaker to restore audibility. In some cases, when a phone is lifted up to the ear with the hearing aid, a certain part of the frequency region becomes unstable, and may result in feedback for that given frequency region. When the feedback signal exceeds the level of the original signal at the microphone, the feedback loop becomes unstable, possibly leading to audible distortions or howling. To stop the feedback, sometimes the gain may need to be turned down. For example, in some hearing aids that have no feedback suppression, the gain may need to be turned down. Also, sometimes in a hearing aid with feedback cancellation, the gain may need to be turned down when a residual feedback (i.e., the part of the feedback signal that the feedback cancellation system fails to predict) exceeds a level of an original input signal.
The risk of feedback limits the maximum gain that can be used with a hearing aid.
Feedback suppression, especially with landline phone usage with hearing aids, continues to be a challenge for hearing aid wears. Although feedback suppression strategies have been utilized to reduce feedback, there are always trade-offs in terms of artifacts or audibility of portions of the frequency response. All current feedback suppression strategies use the hearing instrument processing capabilities to completely deal with the feedback problem.
Applicant of the subject application determines that another approach for reducing feedback associated with an operation of a phone would be desirable.